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Combined OCE MPO ATM Seminar Series


Wednesdays at 3:00 pm, SLAB 103 (unless stated otherwise)

Jan 09 (Tuesday, 11:00): Dr. Joshua Willis (NASA JPL)

OMG, It's Melting.
Early Results from Oceans Melting Greenland (OMG),
and the Use of Comedy to Communicate About Climate Change

Not Funny: Oceans Melting Greenland (OMG) is an airborne NASA Mission to investigate the role of the oceans in ice loss around the margins of the Greenland Ice Sheet. A five-year campaign, OMG will directly measure ocean warming and glacier retreat around all of Greenland. By relating these two, we will explore one of the most pressing open questions about how climate change drives sea level rise: How quickly are the warming oceans melting the Greenland from the edges?

This year, OMG collected its second set of both elevation maps of marine terminating glaciers and ocean temperature and salinity profiles around all of Greenland. This give us our first look at year-to-year changes in both ice volume at the margins, as well as the volume and extent of warm, salty Atlantic water present on the continental shelf. In addition, we will compare recent data in east Greenland waters with historical ocean observations that suggest a long-term warming trend there. Finally, we will briefly review the multi-beam sonar and airborne gravity campaigns – both of which were completed last year – and their impact on bathymetry maps in the coastal waters around Greenland.

Funny: The first time I showed a funny slide at AGU, it bombed. Badly. "What causes global warming?" I asked an audience of 100 learned colleagues. I pushed the space bar. Up popped a photo-shopped picture of a gigantic Al Gore breathing fire on the Earth...

Silence. Complete silence. Even the crickets were judging me.

Since then, I've completed an entire curriculum at a world-renowned school of funny (The Conservatory Program at Second City, Hollywood), written sketch shows, told funny stories, acted in short and full-length feature films, and practiced. Mostly practiced. A lot. So, did I get better at making global warming funny? Come find out.




Feb 07: Dr. Honghai Zhang (Princeton University)

Robustness of
Anthropogenically Forced Decadal Precipitation Changes
Projected for the 21st Century

Precipitation is characterized by substantial natural variability, including on regional and decadal scales. This relatively large variability poses a grand challenge in detecting anthropogenically caused precipitation changes. Here we use large ensembles of climate change experiments with multiple climate models to demonstrate that, on regional scales, anthropogenic decadal changes in ensemble-mean precipitation (i.e., mean state) are detectable, where "detectable" means the change is outside the range expected from natural variability. Relative to the 1950-1999 period, simulated anthropogenic shifts in precipitation mean state for the 2000-2009 period are already detectable over 36-41% of the globe – primarily in high latitudes, eastern subtropical oceans and the tropics. Anthropogenic forcing in future medium-to-high emission scenarios is projected to cause detectable shifts over 68-75% of the globe by 2050 and 86-88% by 2100. Our findings imply detectable anthropogenic shifts in precipitation mean state over the majority of the planet within the next few decades.

Feb 14: Dr. Brian Mapes (RSMAS)

Professor Grumpy Fiiiinally Swallows the Open-Source Nexus Lingo;
Teaching, Research, Comms & Collabs are Transformed!

In this seminar, I will attempt to convey my newfound enthusiasm for a fantastic nexus of free software for highly collaborative computing: {Jupyter + iPython + GitHub}. I am dizzily imagining whole curricula in this space, perhaps displacing books. My whole research workflow will now be in Jupyter. It's even a communication vehicle: In addition to being a computational code, a Jupyter notebook can also be both an eye-friendly formatted document with math and text and hyperlinks (as well as the code and its resulting figures), and furthermore a slide show! And it is all naturally collaborative – world-shared, mix-and-matchable, yet with traceable contribution histories. If you want to follow along "live", consider doing these instructions and bringing your laptop. Or, just listen and learn.

Feb 21: Dr. Yoshiaki Miyamoto (RSMAS)

A Dynamical Mechanism for Secondary Eyewall Formation

This study proposes that secondary eyewall formation (SEF) of tropical cyclones (TCs) can be attributed to an instability of flow in the free atmosphere coupled with Ekman pumping. Unstable solutions of a 1.5-layer shallow water system are obtained under fast wind speed conditions in the free atmosphere. The instability condition derived in the linear model indicates the importance of the ratio of vorticity to angular velocity, and the condition is more likely to be satisfied when the ratio is large and its radial gradient is positive. In other words, fast angular velocity, low absolute vertical vorticity, small negative radial gradient of angular velocity, and large gradient of vertical vorticity are favorable. Eigenvalue analyses are performed by using a vorticity profile with a secondary maximum with a very small magnitude and a wide range of other parameters.

The growth rate increases with vorticity outside the radius of maximum wind (RMW), the radius of the secondary vorticity maximum, its magnitude, and the Rossby number defined as the ratio of maximum tangential velocity to the RMW multiplied by the Coriolis parameter. Furthermore, the growth rate is positive only between 2 and 7 times the RMW, and it is negative close to or far outside the RMW. These features are consistent with previous observational and modelling studies on SEF. A dimensionless quantity obtained from the unstable condition in the linear theory is applied to SEF events simulated by two different full-physics numerical models. It is observed that the dimensionless parameter increases several hours before a secondary peak of tangential velocity forms, suggesting that the initial process of SEF can be attributed to the proposed theory.

Feb 28: Dr. Matthew Igel (University of California Davis)

The Cloudy Links Between Tropical Bulk-Moisture and Precipitation

The focus of this talk will be on the two-way relationships between moisture, clouds, and precipitation in the tropics. I will begin by discussing the properties of the tropical moisture distribution and the simple, but highly non-linear, way in which precipitation depends on column moisture. This latter relationship is reproduced in a high fidelity, large domain cloud resolving model run in a state of radiative convective equilibrium. Model output will be used to describe the physical pathways that transform atmospheric bulk moisture into surface precipitation. Then, the vertically-integrated column moisture will be broken down into two contributions separated by the base of the melting layer. These new layer moisture quantities will be shown to relate much more intimately with cloud processes and the distribution of cloud types than column moisture. These layers act independently to result in the non-linear coupling between column moisture and precipitation. This result will be confirmed with a combination of AIRS, CloudSat, and GPM satellite observations. Next, I will introduce a new way to use our understanding of precipitation and bulk moisture to construct a simple data-driven global hydrological model. The model is asymptotically integrable and can be used to examine the possible responses of tropical moisture and precipitation to climate warming. This simple analytic model suggests the ensemble of climate models may not simulate a wide enough distribution of possible hydrological responses. Predictions can be related back to process understanding.

Mar 02 (5:00 pm, Wetlab): POSTER SESSION

Mar 07 (Auditorium): Dr. Kerry Emanuel (Lorenz Center, MIT)

Severe Thunderstorms and Climate

Severe thunderstorms, which are often associated with strong winds, hail, and tornadoes, pose substantial threats to people, livestock, and agriculture. While their dynamics are well understood, relatively little is known about how climate change (man?made or natural) might affect such storms. In this talk I will focus on one of the main environmental prerequisites for severe storms: Convective Available Potential Energy (CAPE), which is a measure of the potential energy stored in moist atmospheres that can be released explosively when the potential energy barrier that permits its accumulation breaks. I will discuss the work of my former PhD student that shows, rather unexpectedly, that CAPE usually accumulates over only the 6?8 hours leading up to the storm and that its build?up is strongly controlled by soil moisture. I will present observational evidence for this as well as a very simple theoretical model, and discuss how climate change should affect CAPE and how the new understanding of CAPE may someday allow for seasonal prediction of severe storm activity.

Mar 14: Dr. Igor Kamenkovich (RSMAS)

Observing System Simulation Experiments (OSSEs)
for an Array of Profiling Floats

The Argo array currently consists of more than 3000 instruments that make vertical profiles of temperature and salinity every 10 days over the upper 1500-2000 meters. Biogeochemical Argo floats, profiling to 2000 m depth, are being deployed throughout the Southern Ocean by the Southern Ocean Carbon and Climate Observations and Modeling program (SOCCOM), with the goal of reaching 200 floats by 2020. Both arrays provide a wealth of data with the goal of quantifying the role of the oceans in the global carbon and heat cycle. The spatial and temporal sampling coverage of the data is unprecedented, but still remains too sparse for accurate resolution of fields in the vicinity of sharp fronts and powerful mesoscale variability. Comprehensive analysis is needed to optimize the deployment strategy and to assess the accuracy with which large-scale properties can be derived from these local observations.

This study uses Observing System Simulation Experiments (OSSEs) designed to be relevant to the Argo and SOCCOM projects. The annual mean and seasonal cycle of temperature, salinity, dissolved oxygen and dissolved inorganic carbon are sampled, reconstructed and compared to the original model fields. The reconstruction skill is quantified with the reconstruction error (RErr), defined as the difference between the reconstructed and actual model fields, weighted by a local measure of the spatio-temporal variability. Both the comprehensive and idealized OSSEs demonstrate that the RErr depends on the magnitude of the seasonal cycle, spatial gradients, speed of float movement, amplitude of mesoscale variability and number of floats. These factors explain a large part of the spatial variability in the RErr and can be used to predict the reconstruction skill of the array. Furthermore, our results demonstrate that the SOCCOM array size of 150 floats is a reasonable choice for reconstruction of surface properties and annual-mean 2000 m inventories.

Mar 21 (1:30 pm, Auditorium): Dr. Albert Slap (Coastal Risk Consulting, LLC)

Developing a Climate Technology Start-Up: A Report from the Trenches

The need for resiliency in US coastal cities and around the world has never been greater. The number of flooding events in coastal cities is growing exponentially, along with loss of life and property. The role of climate change in this escalation is becoming more and more evident. Local, state and federal governments are unable to fully respond to this challenge alone. What is the role of non-governmental organizations, academic institutions, and the private sector in supplementing governmental efforts to improve climate resiliency? How do private sector companies develop in response to this need and what opportunities are there for partnerships with academic organizations? How can Public Private Partnerships involving academics and startups be fostered in a way that enhances climate resiliency? This seminar will address these questions and provide an overview of the experience in developing a climate technology business. The seminar is intended to both inform academics of the process, challenges and opportunities involved in developing a start up business, and stimulate conversations on potential partnerships between the public and private sector.

Mar 21 (Auditorium): Dr. Johnna Infanti (RSMAS)

Projections of South Florida Precipitation:
On Uncertainty and Working with Climate Data Users

Mar 27 (Tuesday, 11:00 am): Dr. Ronald Oremland (USGS)

Acetylene Fermentation:
Primordial Biogeochemistry,
the Search for Evidence of Life in the Outer Solar System,
and Maybe some Earthly Bioremediation too

Mar 28: Dr. Emmanuel Hanert (Catholic University of Louvain, Belgium)

High-Resolution Marine Connectivity Modelling in the Florida Coral Reef Tract

High-resolution ocean circulation models are required to simulate the complex and multi-scale currents that drive physical connectivity between marine ecosystems. However, standard coastal ocean models rarely achieve a spatial resolution of less than 1km over the >100km spatial scale of dispersion processes. Here we use the high-resolution unstructured-mesh coastal ocean model SLIM that locally achieves a spatial resolution of ~100m over the scale of the entire Florida Coral Reef Tract (FCRT). By coupling SLIM with a biophysical model of larval dispersal we can track the position of virtual larvae released into the simulated domain. Connectivity matrices are then generated from the positions of the particles at the start and at the end of the simulations. By using different connectivity measures and clustering methods, we can highlight the fine details of the connectivity patterns linking the different reefs of the FCRT. These indicators are then used to pinpoint the reefs that would need to be protected in priority and those that would be best suited to coral restoration projects. Our model is currently the first to simulate larval dispersal with such a high resolution between the thousand reefs composing the FCRT. By individually measuring each site's potential as a larval source or sink, we can provide new insights to reef restoration and protection strategies.

Apr 04: Conor Smith (45-Minute AMP Student Seminar)

Advanced Correction of
Near-Shore Surface Currents from TerraSAR-X Along-Track InSAR
for Wave Contributions

Spaceborne along-track interferometric synthetic aperture radar (along-track InSAR) has been used suc-cessfully to produce estimates of the surface current velocity field on a number of occasions. Along-track InSAR data are comprised of two complex images with a very short time lag, with each pixel containing an amplitude and phase. The phase difference allows a direct measurement of the line-of-sight velocity of the Bragg scattering ripples, which includes contributions of the horizontal surface current as well as the phase velocity of the Bragg ripples and orbital motions of longer waves. To calculate the surface current field, the complicated wave-related contributions to the measured radar velocity need to be estimated and subtracted. Previously, either a single mean velocity correction was used or a spatially varying correction was computed using a relatively simple numerical current-wave interaction model. In areas with large current gradients and spatial depth changes, the resulting complicated surface wave field, such as at our test location at the Co-lumbia River, requires a sophisticated method to estimate the complex corresponding velocity corrections. In this location, a near-shore hindcast model, Delft3D/SWAN, is used to produce 2-D theoretical current fields from which the Doppler velocity correction is calculated. Presented here is new work comparing the Doppler velocity correction to various wave height, breaking and steepness predictions from Delft3D/SWAN as well as to certain artifacts in the SAR data that are related to the wave motions and hold promise to be used as an efficient indicator of the necessary Doppler velocity correction.

Apr 11: Dr. Rita Colwell, SEEDS and RSMAS / DEIC 2018 Distinguished Lecturer
(University of Maryland College Park and Johns Hopkins University)

Global Infectious Diseases: Climate, Oceans, and Human Health

The history of marine biology is closely intertwined with human health, beginning with the oceans serving as a source of food and nutrition and providing an extraordinary diversity of life. More recently, significant advances in technology have brought new discoveries - from the outer reaches of space, where remote sensing monitors on satellites circle the earth, to the ultramicroscopic through application of next generation sequencing and informatics. Although primitive by the standards of today's technology, the early successes of the last century in culturing bacteria, viruses, fungi, and protists from the world oceans comprised the first wave of advancement in marine microbiology and provided a groundwork for studying the microscopic life of estuaries, coastal waters, and the deepest parts of the world oceans. The next wave in understanding microbial life in marine systems was essentially functional, namely determining interactive processes, including interaction of climate and ecosystems with the oceans. It is proposed that we are now in a third wave, focused on the genomics of life systems. In this lecture, examples provided from this sweep of history will be presented, employing the genus Vibrio and a prototype species, Vibrio cholerae, as a useful example of the fundamental linkage of human health to the oceans. This microorganism, the causative agent of cholera and associated with major epidemics, is a marine bacterium with a versatile genetics and recently elucidated genomics based on next generation sequencing and bioinformatics. It is distributed globally in estuaries throughout the world. Vibrio species, both nonpathogenic and those pathogenic for humans, marine animals, or marine vegetation, play a fundamental role in nutrient cycling. They have also been shown to respond to warming of surface waters of the North Atlantic, with the increase in their numbers correlated with increased incident of infections in humans. In summary, marine microorganisms provide a critical indicator of human health and wellness and the ubiquitous vibrios in the world oceans offer a model system.

Apr 18: Juan Pinales (45-Minute AMP Student Seminar)

Apr 25: Alexis Denton (45-Minute AMP Student Seminar)

May 02: Dr. Kerri Pratt (University of Michigan) 

Nov 07: Dr. Yair Cohen (CalTech)